This invention relates to the preparation of pentachlorovinylacetyl chloride.
The structure of the parent acid of the compound prepared by the process of this invention, and of its derivatives, was uncertain for a long time, due to the lack of unambiguous methods of determination (Liebigs Ann. Chem. 600 (1956) 1). For this reason, the alternative name pentachlorocrotonic acid has also found use in the literature (Angew. Makromol. Chem. 60/61 (1977) 1). Only very recently was it possible to unambiguously decide that the structure was that of pentachlorovinylacetic acid.
Pentachlorovinylacetyl chloride has been manufactured in the past by chlorination of 1-ethoxy-pentachloro-1,3-butadiene (A. Roedig and P. Bernemann, Liebigs Ann. Chem. 600 (1956) 1. The latter starting material is, however, not easily accessible, since its yield, when prepared from hexachloro-1,3-butadiene, is only 25 to 30 percent, based on the latter compound. Consequently, a need has continued to exist for a process which produces pentachlorovinylacetyl chloride in a simple and economical manner and with high yields.